1. From the Departments of Oncology and Pathology, St Jude Children's Research Hospital, and University of Tennessee Health Center, Memphis, TN; Department of Pathology and ARUP Laboratories, University of Utah, Salt Lake City, UT; Department of Epidemiology and Health Policy Research, College of Medicine, University of Florida, Gainesville, FL; and Section of Hematology/Oncology, Department of Pediatrics, University of Nebraska Medical Center, Omaha, NE.